#include <stdio.h>
#include <time.h>
#include <windows.h>
#include <stdlib.h>

#define U 1
#define D 2
#define L 3
#define R 4 //蛇的状态，U：上 ；D：下；L:左 R：右

typedef struct SNAKE //蛇身的一个节点
{
    int x;
    int y;
    struct SNAKE *next;
} snake;

//全局变量//
int score = 0, add = 10;     //总得分与每次吃食物得分。
int status, sleeptime = 200; //每次运行的时间间隔
snake *head, *food;          //蛇头指针，食物指针
snake *q;                    //遍历蛇的时候用到的指针
int endgamestatus = 0;       //游戏结束的情况，1：撞到墙；2：咬到自己；3：主动退出游戏。

//声明全部函数//
void Pos();
void creatMap();
void initsnake();
int biteself();
void createfood();
void cantcrosswall();
void snakemove();
void pause();
void gamecircle();
void welcometogame();
void endgame();
void gamestart();

void Pos(int x, int y) //设置光标位置
{
    COORD pos;
    HANDLE hOutput;
    pos.X = x;
    pos.Y = y;
    hOutput = GetStdHandle(STD_OUTPUT_HANDLE);
    SetConsoleCursorPosition(hOutput, pos);
}

void creatMap() //创建地图
{
    int i;
    for (i = 0; i < 58; i += 2) //打印上下边框
    {
        Pos(i, 0);
        printf("■");
        Pos(i, 26);
        printf("■");
    }
    for (i = 1; i < 26; i++) //打印左右边框
    {
        Pos(0, i);
        printf("■");
        Pos(56, i);
        printf("■");
    }
}

void initsnake() //初始化蛇身
{
    snake *tail;
    int i;
    tail = (snake *)malloc(sizeof(snake)); //从蛇尾开始，头插法，以x,y设定开始的位置//
    tail->x = 24;
    tail->y = 5;
    tail->next = NULL;
    for (i = 1; i <= 4; i++)
    {
        head = (snake *)malloc(sizeof(snake));
        head->next = tail;
        head->x = 24 + 2 * i;
        head->y = 5;
        tail = head;
    }
    while (tail != NULL) //从头到为，输出蛇身
    {
        Pos(tail->x, tail->y);
        printf("■");
        tail = tail->next;
    }
}

int biteself() //判断是否咬到了自己
{
    snake *self;
    self = head->next;
    while (self != NULL)
    {
        if (self->x == head->x && self->y == head->y)
        {
            return 1;
        }
        self = self->next;
    }
    return 0;
}

void createfood() //随机出现食物
{
    snake *food_1;
    srand((unsigned)time(NULL));
    food_1 = (snake *)malloc(sizeof(snake));
    while ((food_1->x % 2) != 0) //保证其为偶数，使得食物能与蛇头对其
    {
        food_1->x = rand() % 52 + 2;
    }
    food_1->y = rand() % 24 + 1;
    q = head;
    while (q->next == NULL)
    {
        if (q->x == food_1->x && q->y == food_1->y) //判断蛇身是否与食物重合
        {
            free(food_1);
            createfood();
        }
        q = q->next;
    }
    Pos(food_1->x, food_1->y);
    food = food_1;
    printf("■");
}

void cantcrosswall() //不能穿墙
{
    if (head->x == 0 || head->x == 56 || head->y == 0 || head->y == 26)
    {
        endgamestatus = 1;
        endgame();
    }
}

void snakemove() //蛇前进,上U,下D,左L,右R
{
    snake *nexthead;
    cantcrosswall();

    nexthead = (snake *)malloc(sizeof(snake));
    if (status == U)
    {
        nexthead->x = head->x;
        nexthead->y = head->y - 1;
        if (nexthead->x == food->x && nexthead->y == food->y) //如果下一个有食物//
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            score = score + add;
            createfood();
        }
        else //如果没有食物//
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q->next->next != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            Pos(q->next->x, q->next->y);
            printf(" ");
            free(q->next);
            q->next = NULL;
        }
    }
    if (status == D)
    {
        nexthead->x = head->x;
        nexthead->y = head->y + 1;
        if (nexthead->x == food->x && nexthead->y == food->y) //有食物
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            score = score + add;
            createfood();
        }
        else //没有食物
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q->next->next != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            Pos(q->next->x, q->next->y);
            printf(" ");
            free(q->next);
            q->next = NULL;
        }
    }
    if (status == L)
    {
        nexthead->x = head->x - 2;
        nexthead->y = head->y;
        if (nexthead->x == food->x && nexthead->y == food->y) //有食物
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            score = score + add;
            createfood();
        }
        else //没有食物
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q->next->next != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            Pos(q->next->x, q->next->y);
            printf(" ");
            free(q->next);
            q->next = NULL;
        }
    }
    if (status == R)
    {
        nexthead->x = head->x + 2;
        nexthead->y = head->y;
        if (nexthead->x == food->x && nexthead->y == food->y) //有食物
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            score = score + add;
            createfood();
        }
        else //没有食物
        {
            nexthead->next = head;
            head = nexthead;
            q = head;
            while (q->next->next != NULL)
            {
                Pos(q->x, q->y);
                printf("■");
                q = q->next;
            }
            Pos(q->next->x, q->next->y);
            printf(" ");
            free(q->next);
            q->next = NULL;
        }
    }
    if (biteself() == 1) //判断是否会咬到自己
    {
        endgamestatus = 2;
        endgame();
    }
}

void pause() //暂停
{
    while (1)
    {
        Sleep(300);
        if (GetAsyncKeyState(VK_SPACE))
        {
            break;
        }
    }
}

void gamecircle() //控制游戏
{

    Pos(64, 15);
    printf("不能穿墙，不能咬到自己\n");
    Pos(64, 16);
    printf("用↑.↓.←.→分别控制蛇的移动.");
    Pos(64, 17);
    printf("F1 为加速，F2 为减速\n");
    Pos(64, 18);
    printf("ESC ：退出游戏.space：暂停游戏.");
    Pos(64, 20);
    printf("c语言研究中心 www.dotcpp.com");
    status = R;
    while (1)
    {
        Pos(64, 10);
        printf("得分：%d ", score);
        Pos(64, 11);
        printf("每个食物得分：%d分", add);
        if (GetAsyncKeyState(VK_UP) && status != D)
        {
            status = U;
        }
        else if (GetAsyncKeyState(VK_DOWN) && status != U)
        {
            status = D;
        }
        else if (GetAsyncKeyState(VK_LEFT) && status != R)
        {
            status = L;
        }
        else if (GetAsyncKeyState(VK_RIGHT) && status != L)
        {
            status = R;
        }
        else if (GetAsyncKeyState(VK_SPACE))
        {
            pause();
        }
        else if (GetAsyncKeyState(VK_ESCAPE))
        {
            endgamestatus = 3;
            break;
        }
        else if (GetAsyncKeyState(VK_F1))
        {
            if (sleeptime >= 50)
            {
                sleeptime = sleeptime - 30;
                add = add + 2;
                if (sleeptime == 320)
                {
                    add = 2; //防止减到1之后再加回来有错
                }
            }
        }
        else if (GetAsyncKeyState(VK_F2))
        {
            if (sleeptime < 350)
            {
                sleeptime = sleeptime + 30;
                add = add - 2;
                if (sleeptime == 350)
                {
                    add = 1; //保证最低分为1
                }
            }
        }
        Sleep(sleeptime);
        snakemove();
    }
}

void welcometogame() //开始界面
{
    Pos(40, 12);

    system("title c语言研究中心 www.dotcpp.com");
    printf("欢迎来到贪食蛇游戏！");
    Pos(40, 25);
    system("pause");
    system("cls");
    Pos(25, 12);
    printf("用↑.↓.←.→分别控制蛇的移动， F1 为加速，2 为减速\n");
    Pos(25, 13);
    printf("加速将能得到更高的分数。\n");
    system("pause");
    system("cls");
}

void endgame() //结束游戏
{

    system("cls");
    Pos(24, 12);
    if (endgamestatus == 1)
    {
        printf("对不起，您撞到墙了。游戏结束.");
    }
    else if (endgamestatus == 2)
    {
        printf("对不起，您咬到自己了。游戏结束.");
    }
    else if (endgamestatus == 3)
    {
        printf("您的已经结束了游戏。");
    }
    Pos(24, 13);
    printf("您的得分是%d\n", score);
    exit(0);
}

void gamestart() //游戏初始化
{
    system("mode con cols=100 lines=30");
    welcometogame();
    creatMap();
    initsnake();
    createfood();
}

int main()
{
    gamestart();
    gamecircle();
    endgame();
    return 0;
}